Simbiose de bactérias fixadoras de nitrogênio com feijoeiro-comum em diferentes valores de pH

Abstract

Resumo -O objetivo deste trabalho foi avaliar o efeito do pH do meio de cultivo na eficiência simbiótica de estirpes de Rhizobium, em solo com e sem calagem. Foram realizados experimentos em casa de vegetação, com e sem calagem, e no campo, apenas com calagem. O delineamento experimental utilizado foi de blocos ao acaso com quatro repetições, e os tratamentos foram cinco estirpes de Rhizobium (UFLA 02-100, UFLA 02-68, UFLA 04-195, UFLA 04-202 e CIAT 899), cultivadas em meio de cultura 79 com diferentes valores de pH (5,0, 6,0 e 6,9), e testemunhas sem inoculação, com ou sem nitrogênio mineral. Foram avaliados número e massa de matéria seca de nódulos, massa de matéria seca da parte aérea, eficiência relativa, teor e acúmulo de nitrogênio na parte aérea e nos grãos, número de vagens por planta, número de grãos por vagem e rendimento e massa de 100 grãos. O valor de pH ideal para o meio de cultivo variou com as estirpes e com a variável analisada. Os tratamentos que receberam calagem foram superiores aos demais. No campo, independentemente do pH do inoculante, as populações nativas do solo e as estirpes introduzidas promoveram rendimento de grãos semelhante ao da testemunha com 70 kg ha -1 de N e ao da estirpe referência CIAT 899.Termos para indexação: Phaseolus vulgaris, Rhizobium, acidez, fixação biológica de nitrogênio, inoculante. Symbiosis of nitrogen fixing bacteria with common bean in different pH valuesAbstract -The objective of this study was to evaluate the effect of the culture medium pH in the symbiotic effectiveness of Rhizobium strains in soil, with and without liming. Assays were performed in greenhouse, with and without liming, and in the field, with liming. The experimental design was randomized blocks with four replicates, and treatments were five strains (UFLA 02-100, UFLA 02-68, UFLA 04-195, UFLA 04-202 and CIAT 899), grown in a 79 culture medium with different pH values (5.0, 6.0 and 6.9), and two controls without inoculation: with or without mineral nitrogen. Variables analyzed were number and weight of dry nodules, shoot dry matter, relative efficiency, nitrogen content and accumulation in shoots and grains, number of pods per plant, number of grains per pod, and yield and weight of 100 grains. The optimum pH value for the culture medium varied with the strains and the variable analyzed. Treatments with liming were superior to the others. In the field, regardless of the inoculant pH, the native soil populations and the introduced strains promoted grain yields similar to those of the control with 70 kg ha -1 of N and to those of the reference strain CIAT 899.

Symbiotic Effectiveness and Competitiveness of Calopo Rhizobial Isolates in an Argissolo Vermelho-Amarelo Under Three Vegetation Covers in the Dry Forest Zone of Pernambuco

“…Ideally a large number of strains should be included in these stages, to increase the chance of finding higher efficiency strains for inoculant production (Lima et al, 2009;Chagas Junior et al, 2010;Rufini et al, 2011;Araújo et al, 2012;Calheiros et al, 2013).…”

Rendimento do feijoeiro comum em função da aplicação de fertilizantes minerais nitrogenados em cobertura

“…Outro fator que possivelmente pode ter contribuído para o fornecimento adequado de N para as plantas foi a fixação biológica, através de associações com bactérias do gênero Rhizobium nativas do solo que nodulam as raízes (RUFINI et al 2011), mesmo em áreas onde a cultura está sendo implantada pela primeira vez (LEMOS et al 2003), fornecendo N para cultura do feijoeiro.…”

Agronomic efficiency of Rhizobium strains from the Amazon region in common bean

“…PALAVRAS CHAVE: Phaseolus vulgaris L., rizóbio, fixação biológica de nitrogênio, inoculação na semente Agronomic efficiency of Rhizobium strains from the Amazon region in common bean ACTA AMAZONICA Common bean is a legume capable of biological nitrogen fixation (BNF) through symbiosis with bacteria that fix atmospheric N2, which are able to supply at least part of the nitrogen (N) required by the plant for its development, leading to significant savings in the use of nitrogen fertilizers Oliveira et al 2016;Soares et al 2016). In spite of this ability, factors such as competition among the bacteria introduced and others already established in the soil, along with exposure to adverse environmental conditions such as high temperatures and soil acidity, can compromise the efficiency of inoculation, with reflections on the BNF of the crop (Rufini et al 2011;Fonseca et al 2013;Figueiredo et al 2016;Oliveira et al 2016). To maximize the contribution of BNF, above all in tropical soils where acidity conditions are more accentuated, it is necessary to use strains that are more adapted, competitive, and efficient in the infection process (Ferreira et al 2009;2012;Rufini et al 2011;Fonseca et al 2013).…”

“…In spite of this ability, factors such as competition among the bacteria introduced and others already established in the soil, along with exposure to adverse environmental conditions such as high temperatures and soil acidity, can compromise the efficiency of inoculation, with reflections on the BNF of the crop (Rufini et al 2011;Fonseca et al 2013;Figueiredo et al 2016;Oliveira et al 2016). To maximize the contribution of BNF, above all in tropical soils where acidity conditions are more accentuated, it is necessary to use strains that are more adapted, competitive, and efficient in the infection process (Ferreira et al 2009;2012;Rufini et al 2011;Fonseca et al 2013). In this regard, the aim of this study was to evaluate the agronomic efficiency (AE) in the field of Rhizobium strains isolated from acid soils with high aluminum (Al) content from the Amazon region and compare their AE to that of the reference strain CIAT 899 T and of two controls without inoculation, with and without N from urea.…”

“…The experimental design was of randomized blocks with six replications and six treatments. The treatments involved the individual inoculation of strains UFLA 02-100, UFLA 02-127, and UFLA 02-86, isolated from soils of the Amazonian state of Rondônia and selected for their efficiency in Leonard jars, in pots with soil, and under field conditions (Soares et al 2006;Ferreira et al 2009;2012;Rufini et al 2011); the strain CIAT 899 T , approved by the Brazilian Ministry of Agriculture, Livestock, and Food Supply (Ministério da Agricultura, Pecuária e Abastecimento -MAPA) for production of commercial inoculants for bean seeds; and two controls without inoculation, one with 80 kg ha -1 of N-urea (half at sowing and the other half in topdressing at 20 days after emergence -DAE) and another without N-urea. The three strains of the bacteria with the UFLA code belong to the SBMPBS/UFLA (Biology, Microbiology, and Biological Processes Sector) collection of the Universidade Federal de Lavras.…”